I need Corn expression to trigger lambda on every months 10, 15, 20 and month-end date.
The last day of the month is the tricky part. EventBridge does not have a native way of handling that. You would have to create multiple rules and even so February will always be challenging. You would need a rule for 10, 15, 20 then you would need a rule(s) for the 30s and another rule for the 31s. Then you would have to deal with February. The alternative is to create a Lambda function that runs everyday at a certain time and checks if the day has come to run your application; if so implements one of these two options:
- invokes your code;
- using Boto3, creates a rule in EventBridge to
invoke your code;
The second option may be a better approach because it does not touch your application.